HMI Status P. Scherrer

Page 1 LWS Teams Meeting, March 2008

HMI Status

P. Scherrer


HMI Primary goal

Origin of Solar Variability

• The primary goal of the Helioseismic and Magnetic Imager (HMI) investigation is to study the origin of solar variability and to characterize and understand the Sun’s interior and the various components of magnetic activity.

• HMI produces data to determine the interior sources and mechanisms of solar variability and how the physical processes inside the Sun are related to surface and coronal magnetic fields and activity.


HMI Instrument on SDO

• HMI Instrument

– HMI Optics Package (HOP)

– HMI Electronics Box (HEB)

– Intra Instrument Harness

– Flight Software

X

Z

Y

EVE

AIA

X

Y

Z

HOP HEB

HMI

SDO


All moved in!

HOPHOP

HEBHEB

HarnessHarness


HMI is Ready

• The HMI instrument was delivered to NASA last November

• HMI is integrated onto SDO

• HMI will meet “Level-1” observing requirements

• It is a fine instrument, we are very pleased with it

• There are a few minor issues that must and will be resolved in the coming month or two, e.g.:

– A few flight software issues expected to be resolved by May

– Front window birefringence change with temperature to be explored with spare

• There are a few minor issues that will be resolved after launch, e.g:

– Temperature control method and variations during orbit

– Tuning parameters for data compression - variations with tuning and polarization

• There are a few items to be determined after launch, e.g.:

– “Best” framelist for observing sequence

– Can we combine data from both cameras to compute “Observables”

– The internal structure and dynamics of the Sun and the sources of solar variability


So, the first 6 years work of many got the instrument done

but we are not yet ready for data to flow or to accomplish the science..


1. Convection-zone dynamics and solar dynamo– Structure and dynamics of the tachocline– Variations in differential rotation.– Evolution of meridional circulation.– Dynamics in the near-surface shear layer.

2. Origin and evolution of sunspots, active regions and complexes of activity– Formation and deep structure of magnetic complexes.– Active region source and evolution.– Magnetic flux concentration in sunspots.– Sources and mechanisms of solar irradiance variations.

3. Sources and drivers of solar activity and disturbances– Origin and dynamics of magnetic sheared structures and delta-type sunspots.– Magnetic configuration and mechanisms of solar flares and CME.– Emergence of magnetic flux and solar transient events.– Evolution of small-scale structures and magnetic carpet.

4. Links between the internal processes and dynamics of the corona and heliosphere– Complexity and energetics of solar corona.– Large-scale coronal field estimates.– Coronal magnetic structure and solar wind

5. Precursors of solar disturbances for space-weather forecasts– Far-side imaging and activity index.– Predicting emergence of active regions by helioseismic imaging.– Determination of magnetic cloud Bs events.

Primary Science Objectives


HMI Science Analysis Plan

Magnetic Shear

Tachocline

Differential Rotation

Meridional Circulation

Near-Surface Shear Layer

Activity Complexes

Active Regions

Sunspots

Irradiance Variations

Flare Magnetic Configuration

Flux Emergence

Magnetic Carpet

Coronal energetics

Large-scale Coronal Fields

Solar Wind

Far-side Activity Evolution

Predicting A-R Emergence

IMF Bs Events

Brightness Images

Global Helioseismology

Processing

Local Helioseismology

Processing

Version 1.0w

Filtergrams

Line-of-sightMagnetograms

Vector Magnetograms

DopplerVelocity

ContinuumBrightness

Line-of-SightMagnetic Field Maps

Coronal magneticField Extrapolations

Coronal andSolar wind models

Far-side activity index

Deep-focus v and cs

maps (0-200Mm)

High-resolution v and cs

maps (0-30Mm)

Carrington synoptic v and cs

maps (0-30Mm)

Full-disk velocity, v(r,Θ,Φ),And sound speed, cs(r,Θ,Φ),

Maps (0-30Mm)

Internal sound speed,cs(r,Θ) (0<r<R)

Internal rotation Ω(r,Θ)(0<r<R)

Vector MagneticField Maps

Science ObjectiveData ProductProcessing

Observables

HMI Data


HMI Standard Product Pipeline

HMI Data Analysis Pipeline

DopplerVelocity

HeliographicDoppler velocity

maps

Tracked TilesOf Dopplergrams

StokesI,V

Filtergrams

ContinuumBrightness

Tracked full-disk1-hour averagedContinuum maps

Brightness featuremaps

Solar limb parameters

StokesI,Q,U,V

Full-disk 10-minAveraged maps

Tracked Tiles

Line-of-sightMagnetograms

Vector MagnetogramsFast algorithm

Vector MagnetogramsInversion algorithm

Egression andIngression maps

Time-distanceCross-covariance

function

Ring diagrams

Wave phase shift maps

Wave travel times

Local wave frequency shifts

SphericalHarmonic

Time seriesTo l=1000

Mode frequenciesAnd splitting

Brightness Images

Line-of-SightMagnetic Field Maps

Coronal magneticField Extrapolations

Coronal andSolar wind models

Far-side activity index

Deep-focus v and cs

maps (0-200Mm)

High-resolution v and cs

maps (0-30Mm)

Carrington synoptic v and cs

maps (0-30Mm)

Full-disk velocity, v(r,Θ,Φ),And sound speed, cs(r,Θ,Φ),

Maps (0-30Mm)

Internal sound speed,cs(r,Θ) (0<r<R)

Internal rotation Ω(r,Θ)(0<r<R)

Vector MagneticField Maps

HMI DataData ProductProcessing

Level-0

Level-1


Status of HMI Science Processing Plan Development

• Data analysis pipeline: standard helioseismology and magnetic field analyses will produce “Standard” data products

• “Level-1” Observable program development just now getting started.

• None of the “pipelines” are functioning yet.

• Most pipeline elements need updated software.

• Targeted numerical modeling is proceeding.

• Focused data analysis and science working groups continue to be important.

• Joint investigations with AIA and EVE need development.

• Cooperation with other space- and ground-based projects (SOHO, Hinode, PICARD, STEREO, RHESSI, GONG+, SOLIS, HELAS) needs development.

• After this meeting we will evaluate which pipeline elements must proceed with existing algorithms and code and which will get improvements.

• It is clear that “standard products” will evolve early in the mission.


Summary

• The HMI Instrument is ready to provide key data to study the Sun’s dynamics and magnetism: subsurface flow maps and photospheric vector magnetic fields.

• There are some minor issues, some will be fixed and some we will live with.

• It needs to be in the sky.

• The HMI data analysis plan includes a standard pipeline processing and on demand data analysis tools.

• The analysis pipeline is being developed by the Co-I team, using existing techniques and software.

• Since many Co-Is do not have funding to prepare, some of the planned data products may not be available at the start of the mission.

• Many “Traditional” data product pipelines will be ready if the present rate of development continues.

• Work on the “white boxes” will likely wait until after launch.


More Details on HMI status follow

DONE


HMI status

• Completed mechanical integration with the SDO spacecraft

– Optics package alignment is within the requirement

– MLI closeout was completed (except for a couple access points)

• Completed electrical integration

– Discovered low LVDS isolation resistance which indicated ESD damage to LVDS

– Completed LVDS rework (see “Changes Since PSR” chart)

• HMI completed the stand alone CPT and the observatory CPT#1

• HMI hardware is in flight configuration with the following exceptions

– Flight software update is planned prior to CPT#2

– Need to stake the MLI around the front door

– Closeout MLI around alignment cube

– Remove red tag items


Flight Software Status

• Delivered FSW with known issues and planned software update at observatory

– Developed a list of software updates with SDO Project based on existing software problem reports and targeted improvements

• Incorporate known discrepancies (DAI)

• Incorporate IV&V findings

• Complete high speed bus (HSB) resynchronization development

• Developed software test bed for software testing

• Completed most non-HSB related software changes and testing in work

– Closed 23 of 26 DAIs and all IV&V findings

• Demonstrated most HSB functionality and code is being debugged

– Remaining software verification items will be closed upon completion of the next SWAT

– Test bed will be used for in-house test prior to delivery

– SWAT will be performed upon code update at the observatory level

• Software update does not effect EMI/EMC operating modes and analysis

• Software update is planned for May 15th at the observatory prior to CPT#2 and thermal vacuum test


HMI Observables Performance Issues

In no particular order:

• Some scattered light in column direction, small but not well quantified.

• MTF measurements still include Stim-Tel, data in hand, needs analysis.

• Front window birefringence temp sensitivity, may reduce mag sensitivity

• CCD gain stability not well measured.

• CCD full well less than expected, but meets min requirements.

• Uncertainty best focus setting, but small part of range.

• Gravity release change in distortion, field flatness, etc., never tested but some variations when rotated 90 degrees, but small.

• Strange up-down motion in Lyot tuning motor/waveplate, requires registration

• HSB robustness, possibly fixed – not tested.

• Sequencer has some unexplained failures, but rare

• Almost no solar data during testing, but some

• Flat field not demonstrated at needed level, but close

• Antenna induced jitter avoidance not tested, but small.

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HMI Status P. Scherrer